Lamp transfer and inverting apparatus



July 31, 1 A. w. LAMP ETAL LAMP TRANSFER AND INVERTING APPARATUS FiledDec. 26, 1957 5 Sheets-Sheet 1 Inlw ve Sm n v ar

omwgv n w LOU mim A P a n u 9 T July 31, 1962 A. w. LAMP ETAL LAMPTRANSFER AND INVERTING APPARATUS 3 Sheets-Sheet 2 Filed Dec. 26, 1957smmM m T63O OLS 1T Twk i nvMWW u .W Vh e 2* w y 1962 A. w. LAMP ETAL3,047,166

LAMP TRANSFER AND INVERTING APPARATUS Filed Dec. 26, 1957 3 Sheets-Sheet3 Irv/an hers: Av thuv W. Lamp, (161% R. Mecl str-oth,

ThEIT' Attovne9 3,047,166 LAMP TRANSFER AND INVERTING APPARATUS ArthurW. Lamp, Lyndhurst, and Carl R. Meckstroth,

South Euclid, Ohio, assignors to General Electric Company, a corporationof New York Filed Dec. 26, 1957, Ser. No. 705,208 2 Claims. (Cl. 2141)This invention relates to apparatus for the manufacture of electriclamps of the double ended type having a mount sealed into each endthereof, to lamp trans-' fer mechanism for transferring a lamp from onemanufacturing machine to a second manufacturing and assembling machine,and more particularly to an apparatus for sealing the mount into theopposite ends of the tubular envelope of the lamp.

In the manufacture of tubular fluorescent lamps of the type in generaluse at present, a separate lamp mount or stem assembly, comprising aglass steam having lead-in wires sealed therethrough and supporting anelectrode thereon, is sealed into each end of the tubular glass lampenvelope. The sealing operation is generally carried out on a sealingmachine customarily comprising a horizontal turret which supports andholds the tubular lamp envelope in a vertical position with its lowerend resting on the glass stem portion of the lamp mount, and thenindexes the so positioned envelope and mount to a series of sealingstations where they are suitably heated, as by gas tires, to fuse andseal the envelope end to the glass stem of the mount.

After the sealing of one end of the lamp, the lamp is removed from thesealing turret, turned end for end, and then placed back in the same ora second sealing turret with its lower unsealed end in sealing relationto another lamp mount on the second turret. The turning of the lamp endfor end may be carried out either manually or automatically. Where theinverting operation is manual, it is very inconvenient to perform wherethe lamp is of considerable length, such as in the case of the commonsix and eight foot long fluorescent lamp in common use at present.Because of the considerable length, such lamps are unwieldy and awkwardto handle. For such reason, it is difficult to prevent the lamp fromstriking against objects in the immediate vicinity (such as the sealingmachine or other adjacent apparatus) and becoming broken during theinverting operation. Automatic transfer and inverting devices, such asthat shown and described in Patent 2,844,917 issued on July 29, 1958 toRichard D. Caldwell and assigned to the same assignee as the instantapplication, are known. However, difiiculty has been experienced inadapting the apparatus disclosed and claimed in the Caldwell applicationto the transfer of lamps of substantial length, i.e., lamps of the sixand eight foo-t length, due to the limited space available normally inthe factory for performing the transfer and inverting operation.

It is therefore an object of this invention to provide a sealingapparatus for tubular type lamps of substantial length which willoperate to automatically seal one end of a tubular lamp envelope andthen invert the lamp and seal the other end thereof.

Another object of the invention is to provide a lamp manufacturingapparatus having two separate mechanisms verting tubular lamp envelopeshaving substantial length without interfering with or interrupting theoperation of the associated manufacturing processes thereof and withoutdamaging the lamp envelope.

A further object of this invention is to provide a double-turret typeautomatic sealing machine for sealing the lower ends of tubular lamp.envelopes of substantial length positioned on each sealing turret,together with a combination transfer and inverting mechanism forautomatically transferring the lamp envelopes from one turret to theother, and positioning them in inverted position on the second turret.

In accordance with one aspect of our invention, two conventional turrettype lamp sealing machines are positioned in adjacent side by siderelation to support lamps vertically and with a common drive means forindexing them in timed relation with each other, and two transfer armsprovided with lamp gripping means and operating in timed relation to theindexed movements of the sealing turrets are mounted in a positionbetween the two sealing turrets; the first arm is arranged to grip thelamp at the unloading station at one of said turrets and at a pointsubstantially to one side of the mid-point of the lamp and then swing ina horizontal plane and rotate the lamp about a horizontal axistransverse to the lamp axis to simultaneously transfer and rotate thelamp to the horizontal position and place it in position wherein it isgripped by the second transfer arm at a point on the opposite side ofits mid-point from that gripped by the first arm; the second transferarm further rotates the lamp about a horizontal axis transverse to thelamp axis to the vertical position and simultaneously transfers the lampto the second sealing machine at the loading station of the turretthereof. Y

Further objects and advantages of the invention will appear from thefollowing detailed description of a species thereof and from theaccompanying drawings.

In the drawings, FIG. 1 is a plan view of a sealing apparatus comprisingthe invention;

FIG. 2 is a fragmentary perspective view of the lamp transfer andinverting mechanism of the sealing apparatus in position fortransferring a lamp envelope from one of the heads of the first sealingturret; and

FIG. 3 is a fragmentary perspective View of the lamp M transfer andinverting mechanisms of the sealing apparatus shown in position at theinstant of transfer of a lamp envelope from one of the transfer arms tothe second transfer arm and further illustrates diagrammatically theoperating mechanism for the transfer arms.

The invention is herein shown and described as applied to apparatus forsealing the stem assemblies or lamp mounts of a tubular discharge lampto the opposite ends of the lamp envelope 1. As shown in FIG. 1, theapparatus comprises a pair of conventional type fluorescent lamp sealingmachines 2 and 3 mounted in adjacent side by side relation on a commonbase or frame 4 and operating in timed relation to each other. Thesealing machines 2 and 3 may be of the general type described andclaimed in U.S. Patent No. 2,434,664-Mal1oy, dated January 20, 1948,employing gas fires to fuse and seal the glass stem assemblies to theends of the glass lamp envelope. The machines each comprise respectivehorizontal turrets or carriers 5, 5 provided with a plurality of heads6, 6', respectively, located at uniformly spaced intervals around theperipheral region of the respective turrets. The turrets 5, 5 aresupported on vertical shafts 7, 7, respectively, journaled in themachine frame 4, and

they are intermittent-1y rotated in a counterclockwise direction intimed relation to each other to successively index or advancetherespective heads 6, 6' to a plurality of work stations A to Q and A toQ, respectively, corre- Patented July 31, 1962 spending in number to thenumber of heads on each turret. The indexing means for the turrets 5, 5may be of any wellknown type, for instance, such as that illustrated inU.S. Patent No. 1,742,453, Stiles et al., and comprising a rotatingdrum-type cam 8, 8 for the respective turret mounted on a common driveor cam shaft 10 and engaging with a plurality of rollers 9, 9,respectively, depending from disks 11, 11 fastened to the respectiveturret support shafts 7, 7.

The heads 6, 6' on the respective turrets 5, 5 each comprises avertically extending spindle 12 (FIG. 2) journaled in the turret andarranged to support on its upper end a conventional type lamp mount inproper sealing position relative to the lower end of a tubular lampenvelope 1 held in a vertical position in a holder 13 carried by thefinger 12. The holder 13, which may be of the general type disclosed inUS. Patent No. 2,512,277, Jacobsen, comprises opposed pivoted jaws 14,15 which are pivotally mounted on a bracket 16 carried by the spindle 12and normally held in closed position, to grip the lamp envelopetherebetween, by means of a coiled spring 17 anchored at one end to thebracket portion 16 of the holder 13 and connected at its other end to anoperating lever 13 for pivoting the jaws 14, 15.

In the operation of each sealing machine, the lamp mount is placed onthe spindles 12 of the heads 6 or 6 at the mount loading stations B, Bof the respective sealing machines, and the lamp envelope is placed insealing relation in the holder 13 of the head 6 or 6' at the loadingstation C, C of the respective sealing machines, after which the turrets5, 5 index the heads successively through the work stations to Q, Q, atsome of which the glass envelope and glass flare of the mount are heatedby gas fire from burners (not shown) located thereat to effect thefusion and sealing together of the glass parts, and thence to theunloading stations Q, Q where the sealed envelope and mount are removedfrom the respective heads 6 or 6. One end of the lamp envelope 1 issealed in the first sealing machine 2 after which the envelope istransferred to and inserted in an inverted position in the head 6 atstation C of the second sealing machine 3 wherein the other end of theenvelope is then sealed to its respective mount.

In accordance with the present invention, the transfer and inversion ofthe lamp envelope 1 from the first sealing machine 2 to the secondmachine 3 is performed automatically by a transfer mechanism operatingin timed relation to the indexed movements and dwell intervals of thetwo sealing turrets 5, 5. To enable such transfer operation, suitablemeans 21 are provided for first vertically lifting the envelope 1 on thefirst turret 5 off the upper end of its respective spindle 12, at one ofthe stations preceding the unloading station Q (preferably at theimmediately preceding station P as shown in FIG. 1), in order towithdraw the customary exhaust tubes depending from the lower end of theenvelope from the passageway provided therefor in the spindles so as toclear the upper end of the spindles and permit lateral transfer movementof the envelope from the head 6 without breakage of the exhaust tube.The particular lifting means may be similar to that shown in the aboveidentified Caldwell Patent 2,844,917 and is not herein described indetail. Upon completion of such vertical movement by the envelope, thelamp envelope 1 is supported by the holder 13 at a suificiently highelevation above the spindle 12 that at the subsequent station, uponindexing, the lamp envelope may be moved laterally without interferenceof the exhaust tube with its associated spindle.

Upon indexing of the elevated envelope 1 to the unloading station Q itis picked up by the transfer mechanism and then simultaneously turnedend for end and transferred into the head 6 at the loading station C ofthe second sealing turret 5. The transfer mechanism for accomplishingthis operation comprises a first horizontally extending transfer arm 22and a second horizontally extending transfer arm 23 located between thetwo turrets 5 and 5. The transfer arms are similar to that described inthe above identified Caldwell Patent 2,844,917 and need not be fullydescribed here. Briefly, however, each transfer arm comprises a hollowshaft rotatably supported on a housing 24, 24' (FIGS. 2 and 3) which ismounted on the upper end of a vertically extending hollow support shaft25, 25. The shaft 25, 25' is rotatably supported on an upstanding openwork support column or standard 26, 26' which is fastened at its lowerend on a stationary table portion 27, 27' of the machine framework.

The first transfer arm 22 is oscillated in a horizontal plane betweenthe initial lamp pickup position (as shown in the solid lines in FIG. 1)wherein it grips a lamp envelope I in the head 6 at station Q, andintermediate delivery position (as shown by the dotted lines in FIG. 1)wherein it places the said lamp, partially inverted and in a horizontalposition, in the second transfer arm 23 which is in an intermediate lamppickup position (shown by the dotted lines of FIG. 1). The secondtransfer arm 23 is oscillated in a horizontal plane between theintermediate lamp pickup position (shown in dotted lines in FIG. 1)wherein it grips the lamp envelope therein deposited by the firsttransfer arm 22, and a final delivery position (as shown by the solidlines in FIG. 1) while simultaneously rotating the envelope, wherein itplaces the said lamp, now completely inverted, in the head 6' (ashereinafter more fully explained) at station C of the second turret 5'.The swinging movement or oscillation of the transfer arms 22, 23 iseffected by more or less vertically extending lever arms 28, 28' whichare .pivoted at their lower ends by means such as pins 29' on stationarybrackets (not shown), mounted on the base 35 or bed of the machine. Attheir upper ends the arms 28, 28' are pivoted to one end of connectingrods or links 30, 30 the other ends of which are pivotally connected tocrank arms 31, 31' fastened to the lower ends of the vertical supportshafts 25, 25'. The lever arms 28, 28' carry rollers 32, 32' at a pointintermediate their ends, which rollers 32, 32' ride in the cam groove ofthe face cam 33, 33' mounted on the cam shaft 10.

Adjacent its outer or free end, each transfer arm 22, 23 carries anenvelope holder 34, 34. The construction and operation of this holder isdescribed in detail in the above identified Caldwell Patent 2,844,917and is therefore not fully described herein. Briefly, however, eachholder comprises a pair of envelope engaging jaws 35, 35' and 36, 36arranged to be opened and closed through the operation of double actingoil cylinders 37, 37'. The lamp envelopes 1 are gripped and held in afixed position between the jaws 35, 36 and 35, 36' during the lamptransfer operation. As more fully described in the above identifiedCaldwell Patent 2,844,917, operation of the hydraulic cylinders 37, 37actuates the jaws 35, 35 and 36, 36' of the envelope holders 34, 34'into either their open or closed position, depending upon the directionof actuation of the hydraulic cylinders 37, 37. The bydraulic cylinders37, 37' are actuated by a supply of oil under pressure by means of rigidoil lines or conduits 33, 38' and 39, 39' which are connected throughconnector blocks 40, 40 to flexible oil lines 41, 41 and 42, 42'connected to four-way control valves 43, 43' which are actuated by thecontact of their rollers 44, 44 with cams 45, 45' on the main cam shaft10 to thereby control the supply of oil to, and therefore the operationof, the hydraulic cylinder in timed relation to the indexing and dwellperiod of the sealing machines.

The transfer arm 22 is rotated to effect the rotation of the lampenvelope 1 during the interval when the transfer arm is swinging fromits lamp pickup to its lamp 1 delivery position so that the lampenvelope 1 is rotated from a vertical to a horizontal position, and thesecond transfer arm 23 is rotated to effect rotation of the lamp 7envelope 1 from the horizontal to the vertical position during theinterval when the transfer arm is swinging from its lamp pickup positionto its lamp delivery position for the second sealing machine 3. Themechanism and operation necessary to effect rotation of these arms ismore fully described in the above referenced Caldwell Patent 2,844,917,and therefore is not described in detail herein. Briefly, however, therotation of the transfer arms 22, 23 is effected by means of verticallyextending slide rods 46, 46' extending through the hollow verticalsupport shafts 25, 25 and into the support housings 24, 24' and carryingat their upper ends vertically extending rack gears 47, 47' which meetwith spur gears (not shown) fastened to the transfer arms 22, 23 withintheir respective housings 24, 24'. The rack gears 47, 47 are verticallyslidable within the housings 24, 24 so as to rotate the transfer arms22, 23 about their longitudinal axes. At their lower ends the slide rods46, 46 are pivotally connected, by ball and socket connections, to oneend of more or less horizontally extending levers 48, 48' pivoted attheir other end on brackets 49, 49 upstanding from the machine headplate base 4. Intermediate their endsthe levers 48, 48' carry rollers50, 50' which ride in the cam grooves of face cams 51, 51' fastened onthe cam shaft 10.

Upon indexing of a lamp envelope 1 to the lamp transfer station Q of thefirst turret 5, the envelope engaging jaws 35 and 36 carried by theenvelope holder 34 of the first transfer arm 22 are first closed by theoperation of the hydraulic cylinder 37 (as previously explained) so asto cause the said jaws to firmly grip the envelope 1 of the lamp whichis at such time held in the holder 13 on the turret 5. The arm 22 is atan elevation such that it grips the lamp envelope 1 well below itsmid-point. After the lamp has thus been gripped by the transfer armholder 34,

the grip of the holder 13 on the lamp is then released by the opening ofthe jaws 14 and 15 thereof through the operation of a horizontallyextending actuating lever 52 which is pivoted on the stationary columnas and which engages at one end with and depresses the jaw-opening lever18 of the holder 13. The other end of the holder actuating lever 52 isconnected by a vertically extending link 53 (FIG. 1) to an intermediatepoint of a more or less horizontally extending arm lever 54 pivoted atone end on a support bracket 55 secured to a stationary portion of themachine framework. The other end of the cam lever 54 carries a roller 56which rides on the periphery of an edge cam 57 mounted on the cam shaft1t.

Following the release of the lamp 1 by the holder 13 at station Q, thetransfer arm 22 is then swung clockwise as viewed from above, to itsdelivery position, by the operation of the cam 33, lever 28 andconnecting link 36 (as previousiy described) to deliver the lamp to theenvelope holder 34 of the second transfer arm 23.

Simultaneously with the said swinging movement of the transfer arm 22from its lamp pickup position (as shown by the solid lines in FIG. 1) toits lamp delivery position as shown by the dotted lines in FIG. 1), thetransfer arm 22 is rotated 90 about its longitudinal axis, in acounterclock-wise direction as viewed from its outer end, to rotate thelamp envelope 1 about a transverse axis through the operation of the cam51, lever 48, slide rod 46 and the intermeshed rack gear 47 and spurgear. At the moment the lamp envelope 1 is thus rotated to thehorizontal position, the second transfer arm 23 is in its lamp receivingposition to grip the envelope 1 at a point on the opposite side of itsmid-point from that gripped by the arm 22, as best illustrated in FIG.3. The envelope engaging jaws 35 and 36 of the second transfer arm 23are held in the open position through the action of the hydrauliccylinder 37. With the lamp in the position illustrated in FIG. 3, thejaws 35 and 36' of the envelope holder 34 close around the lamp envelope1 through the operation of the cylinder 37, its associated four-wayacting valve 43' and related cam 45'. The jaws 35 and 36 of the envelopeholder 34 on the first transfer arm 22 are opened by the interaction 6of the hydraulic cylinder 37 with its four-way acting valve 43 andassociated cam 45.

The second transfer arm 23 is then rotated clockwise as viewed fromabove from its lamp pickup position (as shown by the dotted lines inFIG. 1) to its lamp delivery position (as shown by the solid lines inFIG. 1) by the action of the cam 33, lever 28 and connecting link 36'.Simultaneously with the movement of the transfer arm 23 from its lampreceiving position to its lamp delivery position the transfer arm 23 isrotated counterclockwise as viewed from its end by the action of cam 51,lever 48' and slide rod 46' so as to rotate the lamp envelope about atransverse axis from the horizontal position to a vertical position andthereby completely invert the lamp through 180 from its initial verticalposition.

After the lamp envelope 1 has been delivered to the intermediateposition by the first transfer arm 22, the first transfer arm 22 isrotated about its longitudinal axis back through 90 to return theenvelope holder 34 to its initial vertical position through theinteraction of lever 48, cam 51' and slide rod 46. Simultaneously, thefirst transfer arm 22 is swung from its lamp delivery position to itslamp pickup position, the envelope engaging jaws 35 and 36 of theenvelope holder 34 being held open by the action of the hydrauliccylinder 37. The first sealing machine 2 has meanwhile indexed onestation during the above described movements of the first transfer armfrom the time it received a lamp, and the turret 5 is presently in adwell period. The envelope holder 34 will now engage the lamp that hasbeen indexed to station Q to repeat the cycle of operation.

Upon delivery of the lamp envelope by the second transfer arm 23 to itsdelivery position at station C of the second lamp sealing machine 3, thelamp is delivered to the lamp holder 13 of the head 6' which at thattime is located at the loading station C, the said holder 13 having beensupplied at one or the other of the preceding two stations A or Bf witha lamp mount on the upper end of its spindle 12 for sealing into theremaining open end of the lamp envelope. The lamp is held vertically bythe jaws 35' and 36' of the envelope holder 34', and is at the envelopeloading station C of turret 5', the turret 5' being in a dwell periodand the head 6' of the turret 5" being in position to receive the lamp.The jaws 14 and 15 of the holder 13 at station C are held in their openposition against the bias of their retaining spring 17 which normallyholds the jaws in the closed position, through the operation of ajaw-opening finger 58 which is carried by a vertically extending sliderod 59 and which on downward movement engages with and depresses thejaw-opening lever 18 of the holder. The slide rod 59 is verticallyreciproeable in a bearing 60 mounted on a stationary portion of themachine framework and is pivotally connected at its lower end to one endof a horizontal-1y extending lever 61 which is pivoted intermediate itsend on a bracket 62 mounted on themachine framework. At its other end,the lever 61 carries a roller 63 which rides on the periphery of an edgecam 64 mounted on the cam shaft 10.

When the lamp envelope 1 has been thus inserted by the second transferarm into the holder 13 at station C of the second turret 5', the jaws 14and 15 of the said holder are then closed against the envelope of thelamp by the elevation and disengagement of the jaw-opening finger 58from the jaw-opening lever 18 of the holder which then allows thebiasing spring 17 thereof to close the holder jaws 14, 15 against thelamp envelope 1 so as to grip and firmly hold it in place in the head6'. With the lamp thus held by the holder 13 at station C, the jaws 35and 36' of the transfer arm holder 34' are opened by the operation ofthe hydraulic cylinder 37 to release the lamp envelope 1 from thetransfer arm holder 34', thereby completing the transfer and inversionof the lamp from the first sealing machine 2 to the second sealingmachine 3. The second transfer arm 23 is then swung in a horizontalplane and rotated about its longitudinal axis back to its lamp pickupposition in readiness for the next lamp transfer operation to receiveanother lamp envelope from the first transfer arm 22. Upon subsequentindexing of the second turret and positioning of the transferred lamp 1at one of the ensuing stations (cg. station D) the lamp is moveddownwardly in the holder 13, by suitable lamp pushdown mechanism (notshown, but similar to that at station D of the first sealing machine 2),into proper sealing relation with the lamp mount resting on the upperend of the spindle 13 of the head 6, with the open lower end of the lampenvelope abutting against the glass lower portion of the lamp mount. Thelamp mount is then sealed to the lamp envelope in the customary mannerby the conventional gas fires (not shown) located at the subsequentindexing station of the turret 5' after which the lamp is elevated, bymechanism similar to that at station P of the first turret 5, and thenremoved from the turret 5'. Another lamp mount is then placed inposition on the spindle 13 of the empty head 6' in readiness for thenext sealing cycle.

It will be seen that tubular lamp envelopes of substantial length, e.g.,of about six or eight foot lengths, may have mounts automatically sealedin both ends thereof according to the present invention and that saidlamps may automatically be inverted and delivered from a first lampmanufacturing machine to a second lamp manufacturing machine. Further,while one specific embodiment of the invention has been described, manymodifications will occur to those skilled in the art. It is therefore tobe understood that the invention is to be limited only by the claimsannexed to and forming a part of this specification.

What we claim as new and desire to secure as Letters Patent of theUnited States is:

1. In combination with means to support vertically extending tubularlamp envelopes at an initial pick-up position and means to support saidenvelopes vertically at a final delivery position spaced horizontallyfrom said pickup position, an inverting transfer mechanism comprisingfirst and second horizontally extending transfer arms mounted forrotation about their respective longitudinal axes and for pivotaloscillation in a common horizontal plane about respective vertical axesspaced apart horizontally between said pick-up and delivery positions,envelope gripping means on the ends of said arms, means for actuatingthe gripping means on said first arm to closed position with the arm atsaid initial pick-up position to grasp an envelope thereat, means forpivotally oscillating said first arm in said common horizontal plane toan intermediate delivery position whereat it extends substantiallynormal to a-horizontal line joining the vertical pivot axes of the twoarms, means for rotating said first arm 90 about its longitudinal axisduring its oscillation so that the envelope held thereby extendshorizontally at the intermediate delivery position of the arm, means forpivotally oscillating said second arm in said common horizontal plane,the lastnamed means holding said second arm, upon arrival of said firstarm at its intermediate delivery position, in an intermediate pick-upposition wherein it also extends substantially normal to the said linejoining the vertical pivot axes of the two arms so that its grippingmeans is in alignment with the gripping means on the first arm andreceives therein a portion of the envelope spaced from the portiongripped by the first arm, means for actuating the gripping means on saidsecond arm to closed position with the second arm at said intermediatepick-up position to grasp the envelope therein, means for then actuatingthe gripping means on the first arm to open position to release its gripon the envelope, the means for pivotally oscillating said second armbeing operable to then oscillate the second arm to the final deliveryposition, and means for rotating said second arm about its longitudinalaxis during its oscillation to the final delivery position, thelastnamed means rotating the second arm in the same angular sense assaid first arm to thereby complete inversion of the envelope through 2.In combination with means to support vertically extending tubular lampenvelopes at an initial pick-up position and means to support saidenvelopes vertically at a final delivery position spaced horizontallyfrom said pick-up position and at substantially the same elevation assaid initial pick-up position, an inverting transfer mechanismcomprising first and second horizontally extending transfer arms mountedfor rotation about their respective longitudinal axes and for pivotaloscillation in a common horizontal plane about respective vertical axesspaced apart horizontally between said pick-up and delivery positions,the said common horizontal plane of oscillation of said arms being at anelevation spaced substantially from the mid-point of an envelopesupported at said initial pick-up and final delivery positions, envelopegripping means on the ends of said arms, means for actuating thegripping means in said first arm to closed position with the arm at saidinitial pick-up posi- A tion to grasp an envelope at a location to oneside of its mid-point, means for pivotally oscillating said first arm insaid common horizontal plane to an intermediate delivery positionwhereat it extends substantially normal to a horizontal line joining thevertical pivot axes of the two arms, means for rotating said first arm90 about its longitudinal axis during its oscillation and in a directionsuch that the longer unsupported length of the envelope rotates awayfrom the said initial pick-up position so that the envelope held therebyextends horizontally at the intermediate delivery position of the arm,means for pivotally oscillating said second arm in said commonhorizontal plane, the last-named means holding said secand arm, uponarrival of said first arm at its intermediate delivery position, in anintermediate pick-up position wherein it also extends normal to the saidline joining the vertical pivot axes of the two arms so that itsgripping means is in alignment with the gripping means on the first armand receives therein a portion of the envelope spaced at the oppositeside of the envelope mid-point from the portion gripped by the firstarm, means for actuating the gripping means on said second arm to closedposition with the second arm at said intermediate pick-up position tograsp the envelope therein, means for then actuating the gripping meanson the first arm to open position to release its grip on the envelope,the means for pivotally oscillating said second arm being operable tothen oscillate the second arm to the final delivery position, and meansfor rotating said second arm 90 about its longitudinal axis during itsoscillation to the final delivery position, the last-named meansrotating the second arm in the same angular sense as said first arm tothereby complete inversion of the envelope through 180".

References Cited in the file of this patent UNITED STATES PATENTS1,524,067 Troutman et al. Ian. 27, 1925 2,540,378 Restetsky Feb. 6, 19512,731,668 Miner Jan. 24, 1956 2,763,098 Pennybacker et al. Sept. 18,1956 2,811,267 Bock Oct. 29, 1957 2,821,810 Bullers et al. 'Feb. 4, 19582,823,815 Doron et al Feb. 18, 1958 2,844,917 Caldwell July 29, 1958

